I think that if you want to be mobile, you can choose one of two paths. The first is the Strobist approach, with relatively inexpensive E-TTL or manual capable speedlights. David Hobby has a fantastic video series on how to get great results. I bought this after seeing him and Joe McNally on the Flashbus tour (which was cool, but this video is a better learning experience). I have a 580 EX, a 430 EX and a 430 EX II, an Orbis ring light, a couple of inexpensive stands, clamps, umbrellas and softboxes. Will try to post some results fairly soon, still getting the hang of it. My challenge is finding the time and good subjects.

The other monolight path is more complicated to use in a mobile setting (i.e. no AC power) because the monolights need some serious batteries. I don't think you can really wade in this pool, you kind of have to dive in. A good balance for quality and cost are the Alien Bees setups, which are sold direct from Paul C Buff website.

I think that if you want to be mobile, you can choose one of two paths. The first is the Strobist approach, with relatively inexpensive E-TTL or manual capable speedlights. David Hobby has a fantastic video series on how to get great results. I bought this after seeing him and Joe McNally on the Flashbus tour (which was cool, but this video is a better learning experience). I have a 580 EX, a 430 EX and a 430 EX II, an Orbis ring light, a couple of inexpensive stands, clamps, umbrellas and softboxes. Will try to post some results fairly soon, still getting the hang of it. My challenge is finding the time and good subjects.

The thing I love about the strobist set-up is how portable it can be. I often work with small light stand, umbrella, 580EX II, and v5 triggers - which makes a great fill light kit for outdoor portraits, and the best part is, I can fit it all in a back-pack, and take it anywhere.

For work inside I just add a few cheap manual flashes, stands, and modifiers, and I'm all set for studio work. The only real drawback to the strobist way is that you need to keep charging batteries, and the recycle times are longer. So if you want to shoot fast, for a long time, studio strobes are better. Also you don't get a modeling light with flashes like you do with studio strobes - and having a modeling light can be very useful to see where your shadows will be.

Not sure how serious you want to get with this? I concur with most here that for now consider additional flash(s), stands and speedring/umbrell or softbox kits for use with flashes for outdoor work until you master it. Even if you moved on to lights/battery packs, you would always have times where you would want to use the ultra-portability of the flash setup. This can also be used with success indoors. The speedring/flashstand kits are inexpensive (and even dirtcheap on ebay, etc.)

As for indoors, monolights are your most economical/professional solution. If purchasing a "2-light" kit of any sort, consider getting minimum 300ws monolights if you can afford it (used equipment is an option as well.) The Alien Bees or Photoflex kits are good in this arena. Also, I highly recommend kits which include the travel bag that holds it all. Some of the shortcomings of cheaper kits are: lack of variable power, no cooling fan, plastic handles (which break/strip - especially when tightening to hold up a big cantilevered softbox!) More power is king - you can always dial it back! Be careful - this sort of thing leads to reflectors, grips, boom arms, hair lights, backgrounds for every occassion . . . . . .

The B&H kit is a constant lighting kit. Basically, 100 watt lightbulbs that stay on all the time. Good for helping you see the light, but hot for your subjects and may not be bright enough to overcome ambient light. It includes items like the green screen that you don't need.

The price doesn't seem all that great.

I agree with others, I would build on your existing kit.

First, you need a way to trigger your 430EXII off-camera. Cheapest ways are with third-party radio transmitter/receivers (as previously mentioned) or third-party infrared triggers. The Yongnuo ST-E2 is less than half the price of the Canon and actually has more features if you go the infrared route. The advantage is that it will work with ETTL, unlike the cheapest radio systems. Infrared can be spotty outdoors, although I've never had a problem with it. Indoors it is very reliable. It's a personal and financial choice (radio systems require a receiver for every strobe, infrared only requires one transmitter with the 430 or 580s.) Even if you eventually go the radio route, having an infrared transmitter can be handy as a backup in case a transmitter or receiver dies on you.

You can do a lot with just the 430EX and an umbrella off-camera. Adding another strobe will give you some more options. Umbrellas are easy to use, almost foolproof for nice, soft flattering light. They build confidence quickly.

Start small and add to your kit. If you think collecting lenses is addictive, wait until you get into lighting. You only need one 70-200mm 2.8 zoom, but you can never have enough strobes and light modifiers.

I bought a 580 EX II Speedlite early on, then got a second one along with PocketWizards when I decided to start messing around with off-camera flash and portraits. But I quickly realized small flash is expensive. So I ended up going with large flash / studio strobes because the cost to flash power ratio was far better with studio strobes.

I'd really love to go small flash for location shooting, but getting 4 to 8 Speedlites is way too expensive when I can get the same flash power out of a couple of studio strobes and battery packs.

One key question - would you have access to AC power in your outdoor location, or need battery packs?

OK... first of all for outdoor shooting 100W strobes are very week... i shoot outdoor portraits using a 300W unit and sometime even at full power is not enough.

Regarding the power packs i use a 1000VA (600W) 2x 12V, 7.4 Ah batteries UPS ... yes the one that is used to keep the PC alive when the electric power is down. I use the UPS for about half a year and dozens of photo shoots. the strobes are ok,UPS is fine... even after 300 pictures ( almost all at full power) i never ( not even once) manage to empty the batteries.

1x dedicated power pack = 7-800$1x 1000VA UPS = 100$

The only downside of the UPS is that is more fragile and not weather sealed.

+ 2 on Syl's book. Even if you are using Canon's RF flashes instead of optical triggering it's still applicable. Buy this book first because it covers extensively what gear you need whether it's strobes or continuous lighting.

+ 2 on Syl's book. Even if you are using Canon's RF flashes instead of optical triggering it's still applicable. Buy this book first because it covers extensively what gear you need whether it's strobes or continuous lighting.

I was looking at this book..and wondering if I should wait a bit to see if he will come out with a revised version for the radio controlled cannon flashes....?